From: Yunsheng Lin linyunsheng@huawei.com
[ Upstream commit 2fb541c862c987d02dfdf28f1545016deecfa0d5 ]
Currently there is concurrent reset and enqueue operation for the same lockless qdisc when there is no lock to synchronize the q->enqueue() in __dev_xmit_skb() with the qdisc reset operation in qdisc_deactivate() called by dev_deactivate_queue(), which may cause out-of-bounds access for priv->ring[] in hns3 driver if user has requested a smaller queue num when __dev_xmit_skb() still enqueue a skb with a larger queue_mapping after the corresponding qdisc is reset, and call hns3_nic_net_xmit() with that skb later.
Reused the existing synchronize_net() in dev_deactivate_many() to make sure skb with larger queue_mapping enqueued to old qdisc(which is saved in dev_queue->qdisc_sleeping) will always be reset when dev_reset_queue() is called.
Fixes: 6b3ba9146fe6 ("net: sched: allow qdiscs to handle locking") Signed-off-by: Yunsheng Lin linyunsheng@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/sch_generic.c | 49 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 33 insertions(+), 16 deletions(-)
--- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -1126,27 +1126,36 @@ static void dev_deactivate_queue(struct struct netdev_queue *dev_queue, void *_qdisc_default) { - struct Qdisc *qdisc_default = _qdisc_default; - struct Qdisc *qdisc; + struct Qdisc *qdisc = rtnl_dereference(dev_queue->qdisc);
- qdisc = rtnl_dereference(dev_queue->qdisc); if (qdisc) { - bool nolock = qdisc->flags & TCQ_F_NOLOCK; - - if (nolock) - spin_lock_bh(&qdisc->seqlock); - spin_lock_bh(qdisc_lock(qdisc)); - if (!(qdisc->flags & TCQ_F_BUILTIN)) set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state); + } +}
- rcu_assign_pointer(dev_queue->qdisc, qdisc_default); - qdisc_reset(qdisc); +static void dev_reset_queue(struct net_device *dev, + struct netdev_queue *dev_queue, + void *_unused) +{ + struct Qdisc *qdisc; + bool nolock;
- spin_unlock_bh(qdisc_lock(qdisc)); - if (nolock) - spin_unlock_bh(&qdisc->seqlock); - } + qdisc = dev_queue->qdisc_sleeping; + if (!qdisc) + return; + + nolock = qdisc->flags & TCQ_F_NOLOCK; + + if (nolock) + spin_lock_bh(&qdisc->seqlock); + spin_lock_bh(qdisc_lock(qdisc)); + + qdisc_reset(qdisc); + + spin_unlock_bh(qdisc_lock(qdisc)); + if (nolock) + spin_unlock_bh(&qdisc->seqlock); }
static bool some_qdisc_is_busy(struct net_device *dev) @@ -1207,12 +1216,20 @@ void dev_deactivate_many(struct list_hea dev_watchdog_down(dev); }
- /* Wait for outstanding qdisc-less dev_queue_xmit calls. + /* Wait for outstanding qdisc-less dev_queue_xmit calls or + * outstanding qdisc enqueuing calls. * This is avoided if all devices are in dismantle phase : * Caller will call synchronize_net() for us */ synchronize_net();
+ list_for_each_entry(dev, head, close_list) { + netdev_for_each_tx_queue(dev, dev_reset_queue, NULL); + + if (dev_ingress_queue(dev)) + dev_reset_queue(dev, dev_ingress_queue(dev), NULL); + } + /* Wait for outstanding qdisc_run calls. */ list_for_each_entry(dev, head, close_list) { while (some_qdisc_is_busy(dev))